Throttle valve



' A. \N. BRUCE THROTTLE VALVE Filed March 28. 1923 WITNESSS PatentedOct. 21, 1924.

ALFIRED W. BRUCE, OF NEW YORK, N. Y.

THROTTLE VALVE.

Application filed- March 28, 1923.

TojaZZ whom it may concern:

Be it known that I, ALFRED WV, BRUCE, of New York, in the county andState of New York, have invented a certain new and useful Improvement inThrottle Valves, of which im rovement the following is aspecific'ation,v

My invention relates to throttle valves of the single poppet type, andits object is to provide a throttle valve of such type which will besimple, and ,compact in construction, and inex ensive in cost ofmaintenance, and in, the operation ofwhich all the advantages of asingle seated valve will be fully attained,

The improvement claimed is hereinafter fully set forth. g

In the accompanying drawing: Figure 1 is a vertical central sectionthrough a throttle valve embodying my invention, ,in operative positionin a steam boiler; Fig. 2,

a horizontal section through the same, on the line a 0; of Fig. 1; and,Fig. 3, a vertical central section, on an enlarged scale, through thevalve, detached.

In the practice of my invention, referring descriptively to the specificembodiment thereof which is herein exemplified, I provide an open toppedthrottle box or chest, 1, which is preferably, as shown, formed integralwith a stand pipe, 2, and is suitably supported in, or adjacent to, asteam boiler, being, in this instance, shown as located in the steamdome, A, of a locomotive boiler. Communication between the steam spaceof the boiler and the stand pipe and connected dry pipe, is controlledby a single sea-ted throttle valve, 3, of the lift or poppet type,connected, with the capacity of a limited degree of relative movement,as hereinafter explained, to a stem, 5, by the longitudinal movement ofwhich it is brought against, or moved away from, an inclined seat, 1*,in the lower portion of the throttle box, 1, to prevent the admissionof, or to admit, as the case may be, steam from the boiler to the drypipe. A cross head, 6, is secured to the valve stem, at its end furtherfrom the valve, for connection to an actuating mechanism for moving thevalve stem and connected valve. Such mechanism, of various types, iswell known in practice, and as it does not form part of my presentinvention, it is not, in detail, herein set forth.

A balancing sleeve, 3*, which is open, at its end further from thevalve, is formed Serial No. 628,258.

integral therewith, and extends therefrom into a superimposed balancingchamber, 4, formed integral with, or secured to, the inside of thethrottle box. The balancing chamber is closed by a removable cap plate,4*, having a properly packed stufling box, 49, through which the valvestem, 5, passes. The sleeve, 3 may either be fitted sufliciently freelyin the balancing chamber to allow a limited degree of leakage of steam.into the chamber, or a small part, 3 may be formed in its wall for thesame purpose. The'se exp'edients are equivalents, and either of themwill perform the essential function of effectin positive. and continuoussteam admission to the balancing chamber.

A central passage, 3", surrounding the valve stem, 5, and of greaterdiameter than said stem, is formed in the throttle valve, 3, and isnormally closed by a pilot valve, 8, fixed on the valve stem. Said stemcarries, adjacent to its lower end, a washer, 5 the position of which isadjustable by a. nut, 5 engaging a screw thread on the stem. The metalof the valve which surrounds the bottom of the central passage, 3', isradially recessed or channeled by grooves, 3 as more clearly shown inFig. 3, to permit the free flow of steam from the passage, 3, when thewasher, 5 bears against the bottom of the throttle valve.

In operation, the throttle valve, 3, being normally seated, it issubjected to downward pressure and held to its seat, by the boiler steamwhich surrounds its sleeve, 3 and, by positive and uninterrupted steamadmission around said sleeve, or through the port, 3, fills thesuperposed balancing chamber, 4t, and exerts downward pressure on thethrottle valve, 3. When it is desired to admit steam to the stand pipe,2, and connected dry pipe, 2 the valve stem, 5, is raised by theactuating mechanism, its preliminary movement unseating the pilot valve,8, and bringing the washer, 5 to a bearing against the bottom of thethrottle valve. The transverse area of the space around the valve stemin the passage, 3*, of the throttle valve is materially greater thanthat of the leakage space allowed around the sleeve, 3*, in theb-alancing chamber, or of the leakage port, 3, if one is provided, andthe steam. in the balancing chamber, 4, is, therefore, immediatelyexhausted therefrom into the stand pipe and dry pipe. The throttlevalve, 3, is thereby relieved from the downward pressure which held it;to its seat, and, by the continued upward movement of the valve stem, 5,which is transmitted to it by the bearing of the washer, 5*, on itsbottom, it may be unseated to any desired degree. There being acontinuous coincident release of pressure n the balancing chamber duringthe period thatithe throttle valve is unseated, no r'e sista-nce isopposed to its upward movement.

The throttle valve is seated by the down ward movement of the stem, 5,in bringing the pilot valve, 8, to its seat, and after being seated, isheld to its seat by the uninterrupted admission of steam into thebalancing chamber.

I claim as my invention and desire to secure by Letters Patent:

1}. The combination of a throttle box,

continuousl 0 en to steam sup lv' a single seated throttle valve,controlling communication between said throttle box and an avenue ofsteam delivery; a superposed balancing chamber, open to said throttlevalve; means for effecting positive and uninterrupted admission of steamto said chamber to exert downward pressure on the throttle valve, whenseated; and means for exhaust ing steam from said chamber, to releasedownward pressure on said valve in effecting its unseating movement.

2. The combination of a throttle box,

avenue of steam delivery; a superposed balancing chamber; a sleeve,fixed to the throttle valve; means for effecting positive anduninterrupted admission of steam to the balancing chamber; and means forexhausting steam from said chamber, to release downward pressure on thethrottle valve in effecting its unseating movement.

3. The combination of a throttle box, con tinuously open to steamsupply; a steam delivery pipe; a single seated throttle valve,controlling communication between said throttle box and said pipe; asuperimposed closed topped balancing chamber, fixed in the throttle box;a sleeve, fixed to the throttle valve and fitting in the balancingchamber, said sleeve having a continuously open steam supply port; astem, connected with the capacity of limited degree of relativemovement, to the throttle valve; and a pilot valve, fixed on said stem,and controlling an exhaust port in the throttle valve. of greatercapacity than the supply port of the sleeve.

ALFRED W. BRUCE.

Witnesses J. RoWDnN BELL, FRED. A. WADSVVORTH.

